Funding for this guide was made available by the Oklahoma State University IPM Program.
Corn represents an important row crop for Oklahoma growers. Field corn is grown predominantly in the Oklahoma Panhandle, north-central and eastern Oklahoma. Acreage devoted to corn production has slightly declined during the past 10 years, averaging 286,000 acres planted, from 1996 to 2000 through 252,000 acres planted from 2001 through 2005. Yields have declined slightly, averaging 140 bushels per acre from 1996 through 2000 and 129 bushels per acre from 2001 through 2005 (NASS, 2006). In 2006, 210,000 acres of corn were harvested (NASS 2008), which produced an average yield of 105 bushels per acre. The top five counties for corn production included Texas, Cimarron, Kay, McCurtain, and Ottawa (NASS, 2006).
A self-administered mailed survey was developed (Dillman, 2007) by T. Franke and K. Kelsey in consultation with Oklahoma Cooperative Extension Service faculty who had expertise in entomology, plant pathology, and plant and soil sciences. The objective of this survey was to identify pest management needs of Oklahoma corn producers and use that information to guide Oklahoma State University’s research and Extension programs in addressing the most critical needs. The survey asked Oklahoma field corn producers to report information regarding their production management practices in regard to soil fertility, insects, and weeds. The population for the study consisted of 1,250 Oklahoma field corn producers in 2006, while the sample consisted of a randomly stratified sample (n = 297). Seventy-four (74) of the 297 surveys were returned (25 percent response rate). The 74 respondents planted 21,758 acres of field corn (average of 294 acres per producer) representing about 8 percent of the total corn grown. It should be noted that 2006 was a severe drought year following several drought years, which may have affected the responses to the survey.
The issues identified by respondents that were of greatest concern with growing corn are listed in Table 1.
Other concerns with growing field corn mentioned by producers included: feed, water, and fuel prices for irrigation (listed once each).
Table 1. Top concerns with corn production identified by Oklahoma survey respondents.
|Issue||High Concern||Moderate Concern||Low Concern||No Concern|
Respondents (79.1 percent) identified soil fertility as the top issue with growing corn. They listed nitrogen deficiency (f = 46) followed by phosphorus deficiency (f = 30) as the most important fertility problems. (Table 2).
Table 2. Soil fertility issues associated with growing corn as identified by Oklahoma survey respondents.
|Low pH (acid soil)||18|
A majority of respondents (73.1 percent) identified weeds as an issue of high concern with growing field corn. Johnsongrass (f = 53), followed by kochia (f = 28) and field bindweed (Table 3). Various herbicides were used to treat weed problems with field corn during 2006. Table 4 notes the herbicides used and the application methods.
Table 3. Weeds encountered in field corn by Oklahoma survey respondents.
|Nutgrass, Crabgrass, Copperleaf & Other||1|
Table 4. Herbicides and number of applications used for weed control in field corn by Oklahoma survey respondents.
|Trade Name (chemical name)||Air||Ground||Other|
|2, 4-D® (2, 4-D)||0||3||1|
|Cinch ATZ® (cynmethylin + atrazine)||0||2||0|
|Bicep® (atrazine + metolachlor)||0||2||0|
|Brawl II ATZ® (atrazine + s-methoachlor)||0||1||0|
|Basis gold® (thifensulfuron + rimsulfuron)||0||1||0|
|Distinct® (sodium salt)||0||1||0|
|Bicep lite® (atrazine + metolachlor)||0||1||0|
|Clarity® (diglycolamine salt)||0||0||1|
Harvest issues were identified as an issue of great concern by more than half of the respondents (55.2 percent). However, respondents were not asked to specify issues associated with harvest. The response shows this issue should be of continued effort for research and Extension educational programs
Insect and Other Arthropods
Less than half of the respondents (47.8 percent) considered insects to be a problem of high concern. Producers noted Southwestern corn borers as the most important insect problem (f = 16) followed by corn rootworms (f = 13) (Table 5). It should be noted transgenic corn produces a natural insecticide to corn borers and is being widely adopted. Insecticides used to treat insect problems and the methods of application are specified in Table 6.
Table 5. Arthropod pests encountered in corn by Oklahoma survey respondents.
|Southwestern Corn Borer||16|
|Seed Corn Maggot||2|
|Western Bean Cutworm||1|
Table 6. Insecticides used in field corn for insect control by Oklahoma survey respondents.
|Trade Name (chemical name)||Air||Ground||Other|
|Mustang MAX® (zeta cypermethrin)||3||0||1|
|Warrior/Karate® (lambda cyhalothrin)||2||0||1|
|Poncho 250® (clothianidin)||0||1||2|
|Penncap-M® (methyl parathion)||1||0|
|Methyl parathion® (methyl parathion)||1||0|
|Force® (lambda cyhalothrin)||0||1|
Less than half of the respondents (43.1 percent) considered plant diseases to be a problem of high concern. However, more than 60 percent listed plant diseases as an issue of high or moderate concern combined. Detailed information was not collected on disease problems because of the low likelihood that fungicides (other than fungicide seed treatments) would be applied to corn in Oklahoma. However, development of research and Extension programs addressing plant disease problems in corn would be valuable to corn producers. It should be noted aflatoxins were identified by respondents as an issue of high or moderate concern combined, which can affect the salability of corn as livestock feed. Thus, development of research and Extension programs addressing plant disease problems in corn would be valuable to corn producers, based on this survey.
Summary and Conclusions
The average Oklahoma field corn producer who responded to this survey grew 294 acres of corn in 2006 and more than half identified soil fertility, weeds, and harvest (unspecified) as issues of high concern. Soil fertility problems consisted of nitrogen and phosphorus. Johnsongrass was the most frequently reported weed problem. Insects and plant diseases were of least concern.
These results suggest corn producers will benefit from research and Extension programs addressing basic and specific pest management challenges. Oklahoma corn producers continue to need information on effective soil fertility, weed management, and harvest issues. While they are less concerned with insect and plant disease management, they would benefit from up-to-date information on management of these pests.
Cronbach, L. (1951). Coefficient alpha and the internal structure of tests. Psychometrika, 16(4), 297-334.
Dillman, D. A. (2007). Mail and Internet surveys: The tailored design method. (2nd ed.). John Wiley & Sons, Inc.: Hoboken, NJ.
Lindner, J. R., Murphy, T. H. & Briers, G. E. (2001). Handling nonresponse in social science research. Journal of Agricultural Education, 42(4), 43-53.
Oklahoma Cooperative Extension Service. “History of Cotton in Oklahoma.” (n.d.). Retrieved from May 20, 2007, from http://www.okstate.edu/ag/oces/cotton_ipm/history.htm
NASS Fact Finders for Agriculture. USDA (Washington, D.C.) 2006 Census of Agriculture State Profile. Retrieved May 18, 2007 from http://www.nass.usda.gov/QuickStats/PullData_US.jsp
Tanya C. Franke
Kathleen D. Kelsey
Tom A. Royer
Professor & IPM Coordinator